Day/night fluctuations in melatonin content, arylalkylamine N-acetyltransferase activity and NAT mRNA expression in the CNS, peripheral tissues and hemolymph of the cockroach, Periplaneta americana
Day/night fluctuations in melatonin content, arylalkylamine N-acetyltransferase activity and NAT mRNA expression in the CNS, peripheral tissues and hemolymph of the cockroach, Periplaneta americana
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DOI：
10.1016/j.cbpc.2004.03.017
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发表时间：
2005-01-01
影响因子：
2.2
通讯作者：
Takeda, M
中科院分区：
文献类型：
--
作者：
Bembenek, J;Sehadova, H;Takeda, M
褪黑激素含量测定的放射性酶法在大脑中的美洲大蠊（美洲大蠊）表现出白天/晚上的波动与更高的水平，在夜间LD 12：12。脑中芳基烷基胺N-乙酰转移酶（NAT）的活性在夜间也较高，这种模式在持续黑暗中持续。结果表明，褪黑素含量的节律性可以由NAT引起。血淋巴中的褪黑素含量表现出更大的昼夜差异，超过12倍，在脑LD 12：12。视网膜中的褪黑激素水平也在夜间较高，而NAT活性在夜间并不显着高于白天。利用从睾丸中克隆的NAT基因设计探针，对总RNA进行北方印迹分析，结果表明：NAT mRNA在中肠、卵巢和雌性附腺中的表达量高于脂肪体和脑。中肠的转录水平在夜间较高，而卵巢和雌性副生殖腺的转录水平则相反。我们还使用了整个果蝇aaNAT 1蛋白的抗体，在头神经节中寻找同源抗原。NAT样抗原在脑中与PER样抗原部分共定位的几个限制性细胞群中检测到。结果表明，NAT以多种形式存在于蟑螂的各种组织中，其功能和调节在不同组织中可能存在差异。大脑中的结果得出结论，NAT可能是一个时钟控制的基因，作为生物钟的输出调节器。(C)2004年爱思唯尔公司All rights reserved.
Melatonin content measured by a radioenzymatic assay in the brain of the American cockroach (Periplaneta americana) showed a day/night fluctuation with higher levels at night under LD 12:12. The activity of arylalkylamine N-acetyltransferase (NAT) in brain was also higher at night and this pattern continued in constant darkness. The results suggest that the rhythmicity in melatonin content can be caused by NAT. Melatonin content in hemolymph showed an even greater day/night difference, more than 12 times that in brain under LD 12:12. Melatonin levels in retina were also higher at night while NAT activity was not significantly higher at night than at daytime. Using a probe designed from NAT cloned from testes we performed Northern blot analysis of total RNA, which revealed that the level of NAT mRNA was higher in midgut, ovary and female accessory glands than in fat body and brain. The level of transcript in midgut was higher at night, but the levels in ovary and female accessory reproductive gland showed the opposite pattern. We also used the antibody to whole Drosophila melanogaster aaNAT1 protein, seeking a homologous antigen in the cephalic ganglia. NAT-like antigen was detected in several restricted populations of cells in the brain that were partially co-localized with PER-like antigen. The results suggest that NAT exists in multiple forms in various tissues of the cockroach and that its functions and regulations can vary among tissues. The results in the brain led to the conclusion that NAT could be a clock-controlled gene functioning as an output regulator of the circadian clock. (C) 2004 Elsevier Inc. All rights reserved.